For a buck, Animated Color Messages from SSA Mobile can add a certain flair to your iOS Messages conversation. It's a simple app to use.
You choose a font, a text color or background pattern, or even a typing animation, and the app constructs a gif for you, pastes it into the system keyboard, and offers to hop you over to Messages.
There, you create a new message, paste, and send it.
The app couldn't be easier to use and a quick store search shows this app category is fairly popular on the store. As these things go, Animated Color Messages was easy enough to use, did what it promised on the package, and offered a range of choices to customize with.
It was a tiny bit of a pain to keep jumping in and out of Messages to compose, send, read, and reply, but the app did the best it could to minimize that pain.
I actually felt the app would be improved with fewer choices and more focus on recommended style combinations. As it is, there's a lot of fonts, tons of colors, and more textures than you could shake a stick at. Joining these into well-designed suggestions could add a way for the app to stand out more tangibly amidst the competition.
The target audience for this app appears to be tween girls.